To all with BIG BOATS!??

For a Mercruiser Alpha drive, the impellor is in the drive unit. Getting the impeller out implies taking the drive off the boat and disassembling the drive. Kinda hard to do in the water. . .but definately can be done on a trailer.

For mercruiser Bravo drives, the "guts" of the drive are large enough such that the pump is moved out of the drive and is mounted on the engine. Replacing THAT pump can be done with the boat in the water. (another reason to escalate to a Bravo drive).

The bravo III drive is a whole different beast, what with the contra rotating props. I am scared of those. :smt043

For all of these drives, I believe the water pickup remains on the drive. Its just a question where the sucking force is coming from.
 
I'm with cr0ck1 on this. Seems like something cheap to have and soemthing that should be done offten.

I have over 20 hours now and I'm sure the 20 hour service they probably didn't replace this but it's obviously important because without it your engine would overheat.

So now I'll be wanting to learn how to do this.

What would be great is if there were a class you could take on general DYI maint on boat motors.
 
Morpheus said:
I'm with cr0ck1 on this. Seems like something cheap to have and soemthing that should be done offten.

I have over 20 hours now and I'm sure the 20 hour service they probably didn't replace this but it's obviously important because without it your engine would overheat.

So now I'll be wanting to learn how to do this.

What would be great is if there were a class you could take on general DYI maint on boat motors.
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imagine how much the dealer would charge to do it.. lol..
 
Cr0ck1:

Your signature says you have a 180 boat. How much did you take off when you hit the sand bar :wink:


Wesley
 
cr0ck1 said:
YES but.. if you flush your engin every time your out.. it will help the life of the impeller!
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I think the sand damage to the impeller is done at the time you pick up the sand and it goes through the system, By the time you get back to the dock, what is done is done; you have abraded the impeller some. Flushing after pulling out is probably not going to get any significant sand out of the impeller, its already through the system.

And it's my opinion that flushing is not going to get the sand out of your engine. If the thermostat is open, and you stir up the sand with your prop, and the engine takes it in, then you will get sand in the passageways of the engine block. You might get some out by flushing, but not all. I think some will settle to the bottom in the block, and be hard to get out.

A couple of months ago I pulled the drain plugs on the bottom of my engine, because I was changing antifreeze and cleaning the system. I had to use a dental pick to clean out the sand at the drain plug so it would drain free. And that is leftover sand from two years ago when I installed fresh water cooling. So it was just in the system (engine, hot water heater, cabin heater), and found its way to the bottom of the block over time.
 
Right. You flush the engine to get recent contaminants out.

If you suck sand. . .you flush with water when running and (hopefully) get it out.

If you run salt water. . you flush with fresh water after running, and get the salt out.

Impeller replacement: The dealer will charge you a fair fortune. In reality, you do the impeller when you do annual drive maintenance (and not every year). When done that way, and important step is already done: Removal and reinstallation of the drive.

In my area, boats get 50 hours per year if well used. Impeller replacement is recommended every *other* year. I think it is a 1-2 hour job, if I recall correctly.
 
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